Field
Embodiments described herein generally relate to a method and apparatus for processing semiconductor substrates, and more particularly, to hydrogenation and nitridization processes modifying effective oxide thickness of a film.
Description of the Related Art
In integrated circuits, smaller transistors, such as metal oxide semiconductor field effect transistors (MOSFETs), are highly desirable. First, smaller transistors enable more transistors to be formed in a given chip area, thereby reducing chip size. Second, smaller transistors can generally switch faster than larger transistors, thereby improving chip performance.
One approach for reducing the size of a MOSFET is scaling, in which important device dimensions are reduced proportionally, such as transistor length, transistor width, and oxide (or dielectric) thickness. In this approach, transistor channel resistance does not change as transistor size is reduced, while gate capacitance and RC delay of the transistor decrease proportionally with the size reduction.
However, while the reduction of dielectric thickness in a MOSFET is crucial for scaling the MOSFET down to the size required by future technology nodes, there is also an important trade-off. Specifically, with a linear reduction of the thickness of the conventional oxide/oxynitride dielectric layer in MOSFETs, there is an exponential increase in gate leakage, resulting in increased power consumption. Moreover, the thickness of the dielectric layer is now close to a few atomic layers, raising reliability concerns. Thus, any means by which oxide thickness or effective oxide thickness (EOT) in a transistor can be reduced without an exponential increase in gate leakage is highly desirable. This and other needs are addressed in the present disclosure.